In the latest release of NSA documents obtained from whistleblower Edward Snowden, The Guardian reveals details of a program called XKeyscore. Among the article’s claims: XKeyscore “allows analysts to search with no prior authorization through vast databases containing emails, online chats and the browsing histories of millions of individuals.”

The NSA’s response to the article is that programs like XKeyscore are vital to national security and that “Allegations of widespread, unchecked analyst access to NSA collection data are simply not true.”